	#!/usr/bin/perl
	# booleans.pl
	use warnings;
	use strict;
	
	use Booleans qw(first second third);
	no Booleans qw(fourth fifth);
	
	print "At Start: \n";
	foreach (Booleans->list) {
	   print "\t$_ is\t:", Booleans->get($_), "\n";
	}
	
	Booleans->set('fifth');
	Booleans->unset('first');
	Booleans->create('ninth', 1);
	Booleans->delete('fourth');
	
	print "Now: \n";
	foreach (Booleans->list) {
	   print "\t$_ is\t:", Booleans->get($_), "\n";
	}
	
	print "By state: \n";
	print "\tSet variables are: ", join(', ', Booleans->list(1)), "\n";
	print "\tUnset variables are: ", join(', ', Booleans->list(0)), "\n";
